Interesting stuff. I like how Perousie is referred to as a nation even though it is still a colony at this point: that implies that independence is really just a slow drifting away from France, rather than a marked event or revolt.
Whatever happened to those hardcore Jacobins who fled into the interior and became a hybrid guerrilla army/Aborigine tribe?
Speculation about the Great American War: At the very least, we know it will directly affect the nations of Antipodea, so that probably means one of the colonizing nations will be involved. I don't see how Belgium or the VOC will be involved, so it's either France or the ENA. Maybe they're at war with one another over a conflict in Louisiana? We do know that Carolina will secede at some point, so that seems possible.
However, the UPSA could also reasonably be involved. They've recently moved into the Philippines and have a big job to do there about de-Spanishizing it. Meridian military will definitely be present, so if a war breaks out between them and either France or North America, they could be quick to go for the colonies.
Slavery is going to be involved, no matter what. The question is, how? The ENA is more or less trying to outlaw the practice, and running into opposition from parts of the southern Confederations, so its conceivable that we have a situation roughly similar to OTL's secession. Louisiana would be caught in an interesting situation here. IIRC, they're still big into the whole slavery thing, and are actively spreading it by expanding the New Orleans-based society into the interior. If the northern ENA is taking a hardline stance, there will be some rumbles in the bayou over this. Hell, Louisiana might get forced into the Carolinan camp. Which means France will probably follow suit.
That's one guess, I haven't thought about the ENS or UPSA in that equation.